I can't speak for other autistic people, but for me there are a few issues with ABA.
1. It seems to me that the whole point of the therapy is to make an autistic person "normal" or at least appear "normal". This is of course impossible, because autistics funcion in a different way from neurotypical people. So not only is ABA therapy useless in this respect, the therapists also charge huge money from despairing parents, by making it seem that they can "cure" their child from autism.
2. Many people who believe in ABA see autism as something bad. In a documentary I saw on autism and ABA last week, a scandinavian independent ABA therapist said that there is nothing good in autism
3. Even though the punishments for "wrong" behavior don't seem to be as drastic now as they were in the 60s and 70s (physical abuse) , when ABA was first used on autistic children, you have to remember where the whole theory behind the therapy comes from. It comes from the notorious doctor Skinner's animal experiments with modifying behavior through reward and punishment.
4.The pace of the therapy. ABA therapy is usually fast-paced, almost manic, because they don't want the child to become fixated on a certain activity. So the activity changes very often, sometimes just after a few seconds. I personally think that some manic therapist, talking really much and behaving very animatedly, making a child switch from activity to activity in a manic way, can almost be considered child abuse.